In general, the driver rotates a steering wheel at a predetermined angle to steer the vehicle. In general, the amount of steering with respect to the rotation angle of the steering wheel is constant. However, in some cases, when the vehicle travels at a low speed, the driver wants to rotate the steering wheel at a small angle to turn the vehicle at a large angle. In addition, in some cases, when the vehicle travels at a high speed, the driver wants to reduce the amount of steering with respect to the rotation angle of the steering wheel to drive the vehicle stably. Therefore, when the amount of steering with respect to the rotation angle of the steering wheel is constant, the convenience of the actual driving operation is low.
For example, Patent Literature 1 discloses a steering device in which the steering wheel can be rotated and tilted in the left-right direction. In the steering device disclosed in Patent Literature 1, the amount of steering with respect to the rotation angle of the steering wheel is changed by the tilt angle of the steering wheel. In the steering device disclosed in Patent Literature 1, when there is a concern that the driver will unintentionally tilt the steering wheel due to the acceleration of the vehicle, the amount of steering with respect to the rotation angle of the steering wheel is maintained constant.